Method and Apparatus of Multicast Service Flow Processing for Headend Cable Modem

1. A method of processing a downstream scheduling of a multicast service flow in a Cable Modem Termination System (CMTS), the method comprising: receiving a multicast packet; determining whether a start address of an inputted downstream data packet corresponds to a multicast group address of the received multicast packet using an ethernet MAC destination address of the inputted downstream data packet; composing a multicast session search character string using an ethernet MAC address denoting a receiving group address of the inputted downstream data packet (GMAC address) and an ethernet MAC address denoting a transmission address (SMAC address); searching multicast session lookup tables to verify whether multicast session information exists; acquiring the start address of a multicast service flow information; searching for service flow information using the start address of the acquired service flow information; composing an internal header in a front portion of the inputted downstream data packet comprising multicast service flow information allocated to a session when the multicast session information about the inputted downstream data packet exists; and composing a multicast MAC packet based on the internal header; and outputting the received multicast MAC packet comprising the composed internal header.

2. The method of claim 1 , wherein, when the multicast session information about the inputted downstream data packet does not exist, the internal header comprising information denoting a broadcast service flow is composed.

3. The method of claim 1 , wherein the internal header comprises at least one of information concerning whether a channel bonding service of the multicast packet is provided, transmission priority information, a downstream channel list, a downstream service flow identifier, and a subsequent link address of a service flow connected with a linked list.

4. The method of claim 1 , wherein after the CMTS receives the multicast packet, the received multicast packet is output having either a first downstream service flow identifier or a second downstream service flow identifier.

5. The method of claim 1 wherein the multicast MAC packet performs downstream scheduling of the multicast packet using the same scheme as a general service flow and a broadcast service flow.

6. The method of claim 5 further comprising transmitting the multicast MAC packet to a downstream physical layer.

7. The method of claim 1 further comprising: determining whether subsequent linked service flow information exists; and acquiring corresponding information when the linked service flow exists.

8. A method of processing a downstream scheduling of a multicast service flow in a Cable Modem Termination System (CMTS), the method comprising: receiving a multicast packet; verifying whether an inputted downstream data packet corresponds to the received multicast packet using a destination address of the inputted downstream data packet; composing a multicast session search character string using an ethernet MAC address denoting a receiving group address of the inputted downstream data packet (GMAC address) and an ethernet MAC address denoting a transmission address (SMAC address); searching multicast session lookup tables to verify whether multicast session information exists when the inputted downstream data packet corresponds to the received multicast packet; acquiring the start address of a multicast service flow information; searching for service flow information using the start address of the acquired service flow information; composing an internal header comprising multicast service flow information allocated to a session when the multicast session information about the inputted downstream data packet exists; and outputting the received multicast packet comprising the composed internal header, and wherein after the CMTS receives the multicast packet, the received multicast packet is output having either a first downstream service flow identifier or a second downstream service flow identifier, and wherein the first downstream service flow identifier comprise at least one of channel bonding and single channel, and wherein the second downstream service flow identifier comprise only single channel.

9. A method of processing a multicast service flow in a Cable Modern Termination System (CMTS), the method comprising: receiving a multicast packet; determining whether a start address of an inputted downstream data packet corresponds to a multicast group address of the received multicast packet using an ethernet MAC destination address of the inputted downstream data packet; composing a multicast session search character string using an ethernet MAC address denoting a receiving group address of the inputted downstream data packet (GMAC address) and an ethernet MAC address denoting a transmission address (SMAC address); searching multicast session lookup tables to verify whether multicast session information exists when the inputted downstream data packet corresponds to the received multicast packet; composing an internal header including information denoting a broadcast service flow when the multicast session information about the inputted downstream data packet does not exist; and outputting the received multicast packet comprising the composed internal header.